This invention relates generally to injection molding and more particularly to an improved method of manufacturing electrically heated nozzles to have a selected one of a number of different gating configurations.
Nozzles of this general type and methods of making them are well known. The basic nozzle and method are described in the applicant's U.S. Pat. Nos. 4,403,405 which issued Sept. 13, 1983 and U.S. Pat. No. 4,446,360 which issued May 1, 1984. A more recently improved method is shown in the applicant's Canadian Pat. No. 1,198,266 which issued Dec. 24, 1985. However, all of these previous methods have the disadvantage that each nozzle has to be made differently to provide a different gating configuration. While these nozzles are commonly used for valve gating and sprue gating, a type of edge gating configuration using hollow edge seals is shown in the applicant's U.S. Pat. No. 4,344,750 which issued Aug. 17, 1982. Another gating configuration which provides a variable size gate is described in the applicant's U.S. Pat. No. 4,579,520 which issued Apr. 1, 1986 entitled "Injection Molding Valve Gated System". The methods of manufacturing nozzles with each of these different gating configuration each involve a number of steps and somewhat different components. Thus, previously it has been necessary to manufacture and maintain a considerable inventory of nozzles for each different type of gating configuration being sold. it will be appreciated that this involves a considerable cost and inevitably there are shortages of one type of nozzle and an excess of another type, depending upon demand.